Conventionally, in an inkjet recording apparatus, maintenance functions for preventing or recovering from a malfunction such as clogging of a nozzle of a recording head are indispensable.
Conventionally, as one of the maintenance functions, a pressure purge for extruding ink from a recording head and a suction purge for sucking out ink from the recording head have generally been known.
Conventionally, an inkjet recording apparatus including a plurality of nozzle heads (recording heads) and having a suction purging function for sucking out ink from the plurality of nozzle heads (recording heads) has been known (see Patent Document 1).
Conventionally, an inkjet recording apparatus having the following configuration having a pressure purging function for extruding ink from a large number of ink discharge channels has been known.
More specifically, in the inkjet recording apparatus, a large number of ink discharge channels are classified into a plurality of groups (head units), a plurality of manifolds for distributing ink from an ink supply source (an ink tank) among the ink discharge channels is provided for each of the groups (head units), and only a valve corresponding to the group (head unit) including the channel on which defective ink discharge occurs is opened, to pressurize and supply the ink with a pump.
Thus, bubbles and thickened ink are forced to be discharged, an amount of ink uselessly consumed to perform a recovery operation is reduced, the possibility that the ink discharge channel from which the ink is normally discharged is closed by the bubbles is reduced, and the recovery operation is efficiently performed in a short time (see Patent Document 2).
Conventionally, an inkjet recording apparatus having the following configuration (see FIG. 3) having a pressure purging function for extruding ink from a plurality of individual heads 151 has been known.
More specifically, during recording, the ink is self-supplied by being discharged out of the individual heads 151 from an intermediate tank 131 via a supply valve 133, a common flow path 134, a distributor 141, and an individual head supply path 145.
The ink is sent by a liquid sending pump 122 from an ink tank 111 via a replenishment flow path 121 when a bulge detection sensor 132 determines that replenishment is required, and is replenished by a predetermined amount to a replenishment valve 123 and the intermediate tank 131.
The distributor 141 provided halfway in the common flow path 134 is provided to make a flow path resistance of ink to be supplied to the individual heads 151 constituting a recording head 150 uniform and functions as a supply source for a short time.
When the recording head 150 is recovered, an atmosphere communication shutoff valve 143 disposed in an upper part of the distributor 141 is opened, to reverse the liquid sending pump 122, and slightly suck air in the distributor 141 serving as a part of an ink flow path, and is closed.
Then, the ink is sent by rotating the liquid sending pump 122 forward, and is extruded by a nozzle of the individual head 151 selected by an individual head valve 146 via a replenishment valve 125 and a pressure flow path 124 for bypassing the intermediate tank 131.
After dripping of the ink from the nozzle of the individual head 151 is stopped, a nozzle surface is wiped by a wiper blade 161 disposed in a maintenance stand 160.
An air vent flow path 171 having an air vent valve 144 is installed from the upper part of the distributor 141, and air is discharged from the flow path during initial introduction of the ink and when air is mixed into an ink supply path (see Patent Document 3).